In April 2019, the Event Horizon Telescope (EHT) collaboration resolved the central black hole of the giant elliptical galaxy Messier 87 (M 87), known as M87*, the first-ever event horizon-scale black hole. I reported the image. . In a new paper, astronomers present new images of M87* from data collected by the Atacama Large Millimeter/Submillimeter Array (ALMA), the Greenland Telescope, and several other instruments within the EHT. doing. These new images show the shadow of his M87* as predicted by general relativity. Interestingly, the peak brightness of the ring is shifted by about 30 degrees compared to the first image. This is consistent with the theoretical understanding of fluctuations due to turbulent matter around a black hole.
The Event Horizon Telescope Collaboration has released new images of M87* from observations taken in April 2018, one year after the first observations in April 2017. The new observations reveal a familiar bright luminescent ring, the same size as the one originally observed. The brightest part of the ring has moved about 30 degrees to the 5 o'clock position compared to the 2017 image. Image credit: EHT Collaboration.
“A fundamental requirement of science is to be able to reproduce results,” says Dr. Keiichi Asada, an astronomer at the Institute of Astronomy and Astrophysics, Academia Sinica.
“The confirmation of the ring in a completely new data set is a major milestone for our collaboration and a strong indication that we are observing the shadow of a black hole and the matter orbiting around it. .”
An image of M87* taken in 2018 is strikingly similar to what astronomers saw in 2017.
They see bright rings of the same size, with a dark central area and one side of the ring brighter than the other.
Because M87*'s mass and distance do not increase appreciably over a human lifetime, general relativity predicts that the diameter of the ring will remain the same from year to year.
The diameter stability measured in the 2017-2018 images strongly supports the conclusion that M87* is well described by general relativity.
“One of the remarkable properties of a black hole is that its radius strongly depends on only one quantity: its mass,” said Dr. Nitika Yadrapalli-Yurku, a postdoctoral fellow at NASA's Jet Propulsion Laboratory.
“M87* is not a material that gains mass rapidly, so according to general relativity, its radius will change little throughout human history. We see our data confirm this prediction. That's very interesting.”
Although the size of the black hole's shadow did not change between 2017 and 2018, the location of the brightest region around the ring changed significantly.
The bright area rotated about 30 degrees counterclockwise and settled in the lower right part of the ring, at about the 5 o'clock position.
Historical observations of M87* with less sensitive arrays and a small number of telescopes also show that the shadow structure changes from year to year, but with low precision.
Although the 2018 EHT array cannot yet observe jets emerging from M87*, the black hole's axis of rotation predicted from the location of the brightest region around the ring is more consistent with the axis of jets seen at other wavelengths. Masu.
“The biggest change is that the brightness peak has moved around the ring, which is actually the first time in 2019 that “This is what we predicted when we announced the results.”
“According to general relativity, the size of the ring should remain approximately constant, but radiation from the turbulent and messy accretion disk around the black hole causes the brightest parts of the ring to move toward a common center. It wobbles around you.”
“The amount of wobble observed over time can be used to test theories about the magnetic field and plasma environment around the black hole.”
of new results appear in the diary astronomy and astrophysics.
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Collaboration with Event Horizon Telescope. 2024. The persistent shadow of M 87's supermassive black hole. I. Observation, Calibration, Imaging, and Analysis. A&A 681, A79; doi: 10.1051/0004-6361/202347932
Source: www.sci.news
